"Due to its close proximity to the Sacramento and San Francisco Bay Area regions, and because of it's varied terrain, Knoxville's 17,700 acres attract many off-highway vehicle (OHV) enthusiasts each year. The landscape is hardwoods and grasses to dense chaparral brush. California gray pine and Macnab cypress are also dispersed throughout the area. Of particular note, are unusual plant communities unique to the area's serpentine barrens, which are closed to vehicles to protect the delicate vegetation.."